Mercedes-Benz is reportedly facing a class-action lawsuit in the U.S. District Court of New Jersey for alleged defects in the company's M156 V8. According to the plaintiffs, premature internal wear occurs because the engine uses cast nodular iron camshafts and 9310-grade steel valves. Something about that combination causes early failure, either due to improper offset of the components or inadequate heat treating. The plaintiffs also allege that Mercedes-Benz and AMG have known about the issue since 2007, when Daimler released a service bulletin on the problem. At this point, it's unclear how many engines this alleged defect covers, or exactly when or if the lawsuit will go to trial.

The M156 V8 – one of the snarliest and best-sounding engines we've ever driven – has served as the powerhouse for a wide range of AMG vehicles. The 6.3-liter lump actually displaces 6.2 liters, but churns out 525 horsepower in its newest iteration. The engine has found its way into vehicles like the C63 AMG, BenzBoost for a look at the full lawsuit.


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  • 40 Comments
      finzenchrome
      • 3 Years Ago
      Try this oxymoron: bad german engineering
      protovici
      • 3 Years Ago
      What about the ticking issue in the new 5.0? Mine did not have the ticking issue, but I know alot of people who do! Of course Ford "doesnt know what it is" and even the new 2012 have the same ticking issue. Watch out!
        diablo000
        • 3 Years Ago
        @protovici
        My L76 6.0L V8 ticks away like mad, but valve train noise is common on LS motors so "eh".
      NY EVO X MR GUY
      • 3 Years Ago
      I know how AMG can avoid a lawsuit. File for bankruptcy and rename their performance division "OMG". Sorry, I could not resist.
      johnb
      • 3 Years Ago
      Maybe Dr. Z should've thrown a Hemi in there instead.
        NightFlight
        • 3 Years Ago
        @johnb
        M156 with issues >>>>> AAANNNYY Hemi
          lostboyz
          • 3 Years Ago
          @NightFlight
          I don't know, a pushrod 6.4L that puts out 10% less HP than this 6.2L for about 1/4 of the cost and better fuel economy isn't all that bad.
          • 3 Years Ago
          @NightFlight
          [blocked]
        dukeisduke
        • 3 Years Ago
        @johnb
        LOL!
      ExoPlanet
      • 3 Years Ago
      Do you hear that? Thats the sound of every M156 6.2L V8 AMG car's value plummeting.
      mbukukanyau
      • 3 Years Ago
      Mercedes should stop selling AMG benzes to lawyers who made their fortunes in class action law suites There should be a clause if the sale contract asking 'are you a class action lawyer'?
      Love Great Danes
      • 3 Years Ago
      Oh no, where will Mercedes get them money for a law suite??? They can't suck it out of Chrysler anymore!
      Flat4
      • 3 Years Ago
      They should have fixed (what sounds like ) the camshaft forging problem a long time ago. Pay up Mercedes and do a recall!
      Dvanos
      • 3 Years Ago
      Doesn't sound good, reminds of the BMW Nikasil lining issue about 10 tens ago.
      Jaylgo
      • 3 Years Ago
      Tick tick tick tick tock tock tock tock tock. I bet that what it sounds like when that engine gives up. CRAP> Mercedes.
      tizzy d
      • 3 Years Ago
      wow, I can't believe this. I am a die hard BMW guy, but I always had a soft spot for the M156 V8, it sounds so good and has so much power.
        Krishan Mistry
        • 3 Years Ago
        @tizzy d
        IMO, the best German 4 seater would have BMW M driving dynamics and an AMG M156 engine powering the rear wheels. Maybe some Audi like styling elements, and either an Audi DSG or a Porsche 7 speed manual.
        jonnybimmer
        • 3 Years Ago
        @tizzy d
        If the xx63 AMGs will fall in value due to this, I for one will be quite happy. Gets me that much closer to having one!
      brian
      • 3 Years Ago
      Too bad - Mercedes hasn't lived up to their historic quality since they bought Chrysler and decided to go into every possible market niche back in the late 90's...
        johnb
        • 3 Years Ago
        @brian
        Actually when they bought chrysler, chrysler had less defects in their cars than mercedes, it took Dr Z a lot of years to drag chrysler down to mercedes level. I'm talking defects, not quality here. Can't really compare a chrysler to a merc in most other ways. Chrysler was on a bit of a roll back then (300/Intrepids/dodge trucks were pretty nice for the time) and that's why they bought them in the first place. Then they just sucked the life outta the brand.
          sjmoo
          • 3 Years Ago
          @johnb
          I apologize for this incessant posting, but that actually isn't true. Back in 1998 (when the merger occurred) only one MB model was ranked poorly and that was the ML. Chrysler, however, did have some really bad cars (along with some excellent cars which you named) with the Jeep Grand Cherokees and minivans being a constant source of recalls for them. That is why Chrysler was consistently below MB in most quality studies at the time. Also, Zetsche actually had very little to do with Chrysler's fall. That was all Jurgen Schrempp who was at the helm of Daimler at the time. He harpooned MB quality and decimated Chrysler of all of its research prowess. He is the one to hate. If it wasn't for Zetsche Chrysler probably wouldn't be here today. He was the one who pushed for joint projects that yielded the 300/Charger, JGC/ML, etc. In essence, the vehicles that kept Chrysler afloat during those dark days.
          NightFlight
          • 3 Years Ago
          @johnb
          sjmoo is correct. Funny to see someone who has actually done some research and knows the FACTS rather than just shouting "Mercedes ruined Chrysler!!!" Chrysler has always ranked poorly as far as reliability is concerned. They actually INCREASED slightly after the merger. Before the merger, what truly great cars did Chrysler have? None.
        sjmoo
        • 3 Years Ago
        @brian
        I disagree. Many of the current MB products are impressively reliable. For example, the W221 actually has fewer problems per hundred vehicles than the W126 according to JD Power. That is progress. Besides, this engine was designed entirely by AMG and this lawsuit is going after Mercedes-AMG, not Mercedes-Benz. It sounds trivial, but that difference is critical here.
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